1. Field of the Invention
The present invention relates to an automatic-and-manual operation composite valve used in an integrated gas supply system for a semiconductor manufacturing apparatus to execute a fluid control.
2. Description of the Prior Art
The integrated gas supply system used for the semiconductor manufacturing apparatus comprises, for example, an integrated gas panel 1 as shown in FIG. 12. In order to control a fluid flow path for the supplied gas, the panel 1 is provided with various valves, a filter 5, a regulator (not shown) or the like in a connectable manner midway of the fluid flow path, and these components can be arranged on a line at a time of being connected. A plurality of such panels are mounted in parallel on a gas supply system (not shown).
A valve for opening and closing the flow path of the panel 1 includes a manual operation valve 2, an automatic operation valve 3, a purge valve 4 and the like. The manual operation valve 2 is intended to open and close the valve with a manual operation handle 2a and normally provided in inlet and outlet sides of the flow path of the panel 1 so as to entirely open and close the flow path. Further, the automatic operation valve 3 is intended to open and close a valve body on the basis of a supply of compressed air, for example, and to optionally operate the valve by remote control into open and close states using an external remote controller (not shown), thereby enabling the gas to be freely supplied to an inflow side and freely discharged from an outflow side. The automatic operation valve 3 presses the valve body in a valve closing direction on the basis of a snapping force of an internally provided spring in a state in which the valve is closed. Thus, it can also serve as a check valve.
As described above, the supplied gas is generally controlled by opening and closing the flow path using the manual operation valve 2 having the manual operation handle 2a or the automatic operation valve 3 having an actuator on the basis of compressed air drive or the like. In the case of a structure in which the functions of a manual operation valve and an automatic operation valve are made integral to form a composite valve, it is possible to make the structure of the panel compact. When the valve is used on the panel, there can be obtained great advantages in that the entire length of an integrated line is shortened, that the number of the component parts can be reduced and consequently that cost can be reduced. Thus, a high utility value can be obtained.
As a valve having both functions of a manual operation valve and an automatic operation valve, there is a composite valve for a gas cylinder in which a cylinder chamber is formed in a valve main body, and a piston housed within the cylinder chamber and connected to a valve body for opening and closing a valve seat can be operated by a pressurized fluid and also with a manual operating handle (refer to Japanese Utility Model Registration No. 2561318, for example). The prior art composite valve has a structure in which a manual operation handle is combined with an air-driven automatic operation valve and operated to make an on-off control of the compressed air of the automatic operation valve.
However, in the case of using the prior art composite valve in which the manual operation handle is combined with the automatic operation valve, the following problems have been imposed. To be specific, when an excessive pressure (1470 Pa or more, for example) is applied to the gas supply side of the valve, the snapping force of the spring of the automatic operation valve cannot restrain a pressing body, the pressure goes over a gas shut-off capacity when the valve is closed, and there is a possibility of the gas leaking out of the outflow side.
Further, since the prior art composite valve has the structure in which the manual operation handle is operated in a state in which supply of the compressed air to the automatic operation valve is not shut off, in case where the pressure in the gas supply side is excessive (1470 Pa or more, for example), there is a possibility of the gas that goes over the shut-off capacity leaking out of the outflow side due to the excessive pressure even when a small amount of air is supplied, because of the presence of inside residual compressed air.
The present invention has been developed taking the conventional problems into consideration, and an object of the present invention is to provide a highly reliable automatic-and-manual operation composite valve having a compact structure and providing both a secure sealing performance of a manual operation valve in a gas supply line and a remote control operability of an automatic operation valve.